Patent GB-567899-A (GB)
Title: Improvements in and relating to cutting-off machines
IPC: B24B27/06
Filed: 1943-06-30
Abstract: 567,899. Cutting-off machines. COMMUNICATIONS PATENTS, Ltd., and DUMBRILL, H. W. June 30, 1943, No. 10645..[Class 60] In an abrasive cutting- off machine, the abrasive wheel is mounted on a carrier operated by hydraulic means to feed the wheel upwardly to effect the cutting-off ; a hydraulically - operated vice for holding the work also is provided, interlocking means between the carrier and vice also being provided to prevent operation of the carrier until the work is gripped by the vice. The machine comprises a casing 6 within which is a carrier 7, upon which the abrasive wheel 9 is mounted, pivoted at 10 and having thereon an electric motor 11 driving the wheel 9 by belting 12. The carrier is moved upwards about the pivot by a hydraulic ram consisting of a cylinder 14 pivoted at 15 within an oil sump 16 and having therein a piston, the rod 17 of which is pivoted to an extension 13 of the carrier 7 ; oil is supplied by a pump 18. The wheel 9 is moved upwards to cut the work through a slot 21 in the top face of the casing, and is returned to inoperative position by gravity. On each side of the slot 21 is one part 22 of a two-part vice, the work to be cut being clamped therein by plungers 23 of hydraulic rams 24, return movement of the plungers being effected by springs 25 ; the rams are mounted in a bracket 26 extending upwardly and forwardly to provide. a guard 27 for the wheel 9. The pump 18 conveys oil, by a conduit 31, to a manuallyoperable distributer 32 comprising two sections with rotatable valve members 33, 34 respectively; an exhaust conduit 35 leads from the distributer to the sump 16 and a non-return valve 36 is located between the conduits 31, 35. Another outlet from the distributer opens into a conduit 37 leading to the rams 24, a non-return valve 38 being placed between the conduit 37 and an inlet conduit 39, and a conduit 40 leads to the cylinder 14, an adjustable valve 41 and a parallel non-return valve 43 being interposed between the distributer and the cylinder ; the lower end of the piston 44 in cylinder 14 has an extension 45 which enters a reduced diameter extension 46 of the cylinder to cushion the gravity return of the carrier 7. The members 33, 34 have therein passages 47, 48 respectively and are operated by a hand lever 49. Three positions for the lever 49 are provided, namely, (a) vice open, no feed of wheel 9, (b) vice closed, no feed, and (c) vice closed, feed ; the positions of the valves for these conditions being indicated in Fig. 3, and in Figs. 4 and, 5 (not shown). In position (a) the oil returns through the valve 36 to the sump and conduit 40 is open to exhaust; in position (b) oil passes to the rams 24, and in position (c) oil passes to the rams 24 and when pressure in the conduit 37 rises sufficiently, also passes to conduit 40 to operate the piston 44, the wheel 9 being returned by gravity when lever 49 is moved back to position (b), and the vice unclamped when the lever is returned to position (a). The wheel 9 is located in a trough 52 containing lubricating or cooling liquid, which may be delivered by a pump to the inside of the wheel guard 27 to act as a coolant, or to the wheel 9 for wet grinding. A variable speed gear may be provided between the motor 11 and the wheel 9 so that the speed of the wheel may be arranged for an optimum peripheral speed ; an indicator, showing the wheel diameter and/or the peripheral speed, may be provided. The interlock between the vice and the carrier may be mechanical.